{smcl}
{* *! version 1.0.0 3jun2014}{...}
{cmd:help treatoprobitsim}{right: ({browse "http://www.stata-journal.com/article.html?article=st0402":SJ15-3: st0402})}
{hline}

{title:Title}

{p2colset 5 24 26 2}{...}
{p2col:{hi:treatoprobitsim} {hline 2}}Estimate effect of potentially endogenous binary treatment on discrete, ordered outcome{p_end}
{p2colreset}{...}


{title:Syntax}

{p 8 23 2}
{cmdab:treatoprobitsim}
{it:depvar} [{it:indepvars}]
{ifin}
{weight}{cmd:,} {opt treat:ment(depvar_t = [varlist_t])}
{opt sim:ulationdraws(#)} [{opt facdens:ity(string)} {opt facsc:ale(real)}
{opt facsk:ew(real)} {opt start:point(integer)} {opt facmean(real)}
{opt vce(string)} {opt sesim:ulations(integer)} {opt mixpi(integer)}]

{phang}
{cmd:pweight}s, {cmd:fweight}s, and {cmd:iweight}s are allowed; see 
{help weight}.


{title:Description}

{pstd}
{cmd:treatoprobitsim} fits a model in which {cmd:treatment()} is a binary
indicator for a treatment ({it:y_treat}) for which selection is believed to be
correlated with the outcome of interest, {it:y_ordered}.  The model assumes
that the unobservables in treatment and outcome equations follow the
distribution specified in {cmd:facdensity()} and that outcomes for treated and
untreated groups are not distinct.  Parameters of the model are estimated by
maximum likelihood.


{title:Options}

{phang}
{opt treatment(depvar_t = [varlist_t])} specifies the participation index
(coded as zero or one).  {cmd:treatment()} is required.

{phang}
{opt simulationdraws(#)} specifies the number of draws from the distribution
of the latent factor.  {cmd:simulationdraws()} is required.

{phang}
{opt facdensity(string)} specifies the density of the latent factor.
{it:string} may be {cmd:normal}, {cmd:uniform}, {cmd:logit}, {cmd:chi2},
{cmd:lognormal}, or {cmd:gamma}.  The default is {cmd:facdensity(normal)}.  

{phang}
{opt facscale(real)} specifies the scale of the latent factor distribution.
The default is {cmd:facscale(1)}.

{phang}
{opt facskew(real)} specifies the skewness of the latent factor distribution
for use with the option {cmd:facdensity(chi2)}. The default is
{cmd:facskew(2)}.

{phang}
{opt startpoint(integer)} specifies the starting point for the Halton-sequence
draws that are used to simulate the latent factor distribution.  The default
is {cmd:startpoint(5)}.

{phang}
{opt facmean(real)} is particularly useful with the {cmd:gamma} distribution
option; because all the latent factors are normalized to mean zero, this
parameter essentially controls the skewness of the gamma distribution used.

{phang}
{opt vce(string)} specifies how to estimate the variance-covariance matrix
corresponding to the parameter estimates.  {cmd:cluster} {it:clustvar}
specifies the cluster standard errors using {it:clustvar}. {opt robust}
computes the robust variance-covariance matrix.

{phang}
{opt sesimulations(integer)} specifies the number of draws of the parameter
vector to be used in computing standard errors of average treatment effects
and average treatment effect for the treated. The default is
{cmd:sesimulations(100)}.

{phang}
{opt mixpi(integer)} specifies the mixing proportion for a two-component
mixture of normals.  The default is {cmd:mixpi(50)}.


{title:Examples}

{pstd}
Order self-assessed health ({bf:sah}) on a 1-5 scale (excellent, very
good, good, fair, poor), and let {bf:mcd} be an indicator of participation in
Medicaid:{p_end}
{phang2}{cmd:. use nhisdataex}{p_end}
{phang2}{cmd:. treatoprobitsim sah female married, treatment(mcd=female married) simulationdraws(200) facdensity(logit) vce(robust)}{p_end}
{phang2}{cmd:. treatoprobitsim sah female married [pweight=normwgt], treatment(mcd=female married) simulationdraws(200) facdensity(logit) vce(robust)}{p_end}


{title:Author}

{pstd}Christian A. Gregory{p_end}
{pstd}Economic Research Service, USDA{p_end}
{pstd}Washington, DC{p_end}
{pstd}cgregory@ers.usda.gov{p_end}


{marker also_see}{...}
{title:Also see}

{p 4 14 2}Article:  {it:Stata Journal}, volume 15, number 3: {browse "http://www.stata-journal.com/article.html?article=st0402":st0402}

{p 7 14 2}Help:  {help treatoprobitsim postestimation} (if installed){p_end}
